This R01 proposal is in response to PA-00-100, Secondary Analysis of Existing Health Services Data Sets. This application to the National Institute on Alcohol Abuse and Alcoholism (NIAAA) proposes 2 years of support for research on national trends, determinants, barriers, and outcomes of treatment utilization for alcohol-related problems in nationally representative samples of household residents in the United States. The proposed research requires no new and costly data gathering. Secondary data analysis will be performed on data files from the 1991 to 1998 National Household Surveys on Drug Abuse (NESDAS) and the National Comorbidity Survey (NCS). Alcohol abuse and/or dependence is one the most prevalent psychiatric disorders among adults in the United States, and it tends to co-occur with other psychiatric disorders. However, there is extremely low prevalence of alcohol abuse treatment utilization among those having an alcohol disorder in the past year. The combination of a high prevalence of alcohol use disorders with a relatively low prevalence of alcohol abuse treatment utilization represents an important public health problem. The specific aims of the proposed study are as follows: (1) provide population estimates of the national trend in alcohol abuse treatment utilization and examine its relationship with demographics, insurance coverage/benefits, and type of treatment settings; (2) determine factors affecting the utilization of different types of alcohol abuse treatment and factors related to unmet needs for treatment; (3) examine the time lag between the onset of alcohol-related problems and first treatment use and factors predicting the delay in seeking treatment; and (4) understand drinking outcomes of prior treatment status and factors that may moderate the relationship between prior treatment status and later drinking outcomes. Findings from the proposed analysis have significant implications. They will (a) provide population estimates on national trends and the magnitude of met and unmet needs for alcohol abuse treatment; (b) specify under served subgroups who can then be targeted to improve their access to treatment; identify determinants of and barriers to treatment service utilization that suggest directions for future research, the planning of treatment service delivery, and policy making; and (d) provide vital information for predicting the potential future burden of alcohol-related problems by subgroups and for guiding future efforts to improve the quality of alcohol-related care.